Removal Procedure
Important: The upper intake does not have to be removed to remove the lower intake manifold.
- Disconnect the breather tube at the air cleaner
outlet duct.
- Remove the air cleaner outlet duct retaining
wingnut.
- Disconnect the IAT sensor harness connector.
- Remove the air cleaner outlet duct from the
throttle body.
- Disconnect the accelerator cable from the throttle
body.
- Remove the accelerator cable from the accelerator
control cable bracket.
- Disconnect the cruise control cable, if equipped from the throttle shaft
and the accelerator cable bracket. Refer to
Cruise Control Cable Replacement
in Cruise
Control.
- Disconnect the vacuum hose from the intake manifold
for the vacuum tank.
- Remove the power brake booster vacuum hose.
- Disconnect the following electrical connectors:
• | The A/C compressor clutch (1) |
• | The A/C compressor cutoff switch (5), if equipped |
• | The throttle position (TP) sensor (2) |
• | The idle air control (IAC) motor (3) |
- Disconnect the following electrical connectors:
• | The fuel meter body assembly (1) |
• | The manifold absolute pressure (MAP) sensor (3) |
• | The EVAP canister purge solenoid valve (2) |
- Remove the engine wire harness clip from the accelerator cable bracket.
- Move the engine wiring harness aside.
- Remove the accelerator cable bracket from the
throttle body and the intake manifold.
- Remove the accelerator and cruise control cable
bracket from the throttle body.
Leave the accelerator and cruise control cables on the bracket.
- Remove the PCV valve hose assembly from the
intake manifold and the valve rocker arm cover.
- Remove the bracket for the engine wiring harness
from the intake manifold stud.
- Remove the fuel lines from the fuel meter body assembly. Refer to
Fuel Hose/Pipes Replacement - Engine Compartment
in Engine Controls - 4.3L.
- Remove the EVAP canister purge solenoid valve. Refer to
Evaporative Emission Canister Purge Solenoid Valve Replacement
in Engine Controls - 4.3L.
- Remove the studs for the upper intake manifold.
- Remove the upper intake manifold.
- Remove the upper intake manifold gasket from
the groove.
- Discard the gasket.
- Remove the seal from the fuel meter body assembly.
- Discard the seal.
Important: Do not immerse the assembled upper intake manifold in cleaning solvent.
- Clean all sealing surfaces and the inside of the upper intake manifold with
a shop towel and cleaning solvent.
- Inspect the upper intake manifold for the following:
• | Cracks or other damage to the exterior |
• | Cracking or damage to the gasket grooves |
• | Loose or damaged bolt hole thread inserts |
• | Damage to the throttle body mounting surface |
- If replacing the upper intake manifold, turn
and remove the power brake booster vacuum tube fitting from the upper intake
manifold.
- Remove and discard the seal.
- If replacing the upper intake manifold, turn
and remove the PCV valve cover from the upper intake manifold.
- Remove and discard the seal.
- Remove the throttle body if replacing the upper intake manifold. Refer
to
Throttle Body Assembly Replacement
in Engine Controls - 4.3L.
- Remove the MAP sensor if replacing the upper intake manifold. Refer to
Manifold Absolute Pressure Sensor Replacement
in Engine Controls - 4.3L.
Installation Procedure
- Install the throttle body, if removed. Refer
to
Throttle Body Assembly Replacement
in Engine Controls - 4.3L.
- Install the MAP sensor, if removed. Refer to
Manifold Absolute Pressure Sensor Replacement
in
Engine Controls - 4.3L.
- Install the PCV valve cover, if removed, using the following procedure:
3.1. | Install a NEW seal (O-ring) on the PCV valve cover. |
3.2. | Lubricate the seal with clean engine oil. |
3.3. | Install the PCV valve cover in the upper intake manifold. |
3.4. | Turn and lock the PCV valve cover in position. |
- Install the power brake booster vacuum tube
fitting, if removed, using the following procedure:
4.1. | Install a NEW seal (O-ring) on the power brake booster vacuum tube fitting. |
4.2. | Lubricate the seal with clean engine oil. |
4.3. | Install the power brake booster vacuum tube fitting in the upper intake
manifold. |
4.4. | Turn and lock the power brake booster vacuum tube fitting in position. |
- Install a NEW seal on the fuel meter body assembly.
- Lubricate the seal with clean engine oil.
- Install a NEW upper intake manifold to lower
intake manifold gasket in the groove of the upper intake manifold.
- Install the upper intake manifold onto the lower
intake manifold.
- If reusing the fasteners, apply threadlock GM P/N 12345382
or equivalent to the threads of the upper intake manifold attaching bolts.
Notice: Use the correct fastener in the correct location. Replacement fasteners
must be the correct part number for that application. Fasteners requiring
replacement or fasteners requiring the use of thread locking compound or sealant
are identified in the service procedure. Do not use paints, lubricants, or
corrosion inhibitors on fasteners or fastener joint surfaces unless specified.
These coatings affect fastener torque and joint clamping force and may damage
the fastener. Use the correct tightening sequence and specifications when
installing fasteners in order to avoid damage to parts and systems.
- Install the upper intake manifold attaching studs.
Tighten
- Tighten the upper intake manifold attaching studs on the first pass to
5 N·m (44 lb in).
- Tighten the upper intake manifold attaching studs on the final pass to
9 N·m (80 lb in).
- Install the fuel lines to the fuel meter body assembly. Refer to
Fuel Hose/Pipes Replacement - Engine Compartment
in Engine Controls - 4.3L.
- Install the EVAP canister purge solenoid valve. Refer to
Evaporative Emission Canister Purge Solenoid Valve Replacement
in Engine Controls - 4.3L.
- Install the bracket for the engine wiring harness
on the lower intake manifold stud.
- Install the engine wiring harness bracket nut.
Tighten
Tighten the engine wiring harness bracket nut to 12 N·m (106 lb in).
- Install the accelerator and cruise control cable
bracket to the throttle body.
- Install the accelerator and cruise control cable bracket nuts.
Tighten
Tighten the accelerator and cruise control cable bracket nuts to 9 N·m
(80 lb in).
- Install the accelerator control cable bracket
to the throttle body and the intake manifold.
Tighten
Tighten the accelerator control cable bracket studs and nuts to 12 N·m
(106 lb in).
- Connect the PCV valve hose assembly to the intake
manifold and the valve rocker arm cover.
- Position the engine wiring harness.
- Install the wire harness clip to the accelerator cable bracket.
- Connect the following electrical connectors:
• | The fuel meter body assembly (1) |
• | The manifold absolute pressure (MAP) sensor (3) |
• | The EVAP canister purge solenoid valve (2) |
- Connect the following electrical connectors:
• | The A/C compressor clutch (1) |
• | The A/C compressor cutoff switch (5), if equipped |
• | The throttle position (TP) sensor (2) |
• | The idle air control (IAC) motor (3) |
- Connect the vacuum hose from the vacuum tank
to the intake manifold.
- Install the power brake booster vacuum hose to the intake manifold.
- Install the cruise control cable, if equipped to the throttle shaft and
the bracket. Refer to
Cruise Control Cable Replacement
in Cruise Control.
- Install the accelerator cable onto the throttle
body.
- Wrap the cable in between the finger of the
hook tab and the pulley wall. Make sure that the cable is fully seated in the pulley
groove. The cable must not lie outside of the hook tab.
- Install the accelerator cable to the accelerator
cable control bracket.
Notice:
• | Handle the MAF sensor carefully. |
• | Do not drop the MAF sensor in order to prevent damage to the MAF
sensor. |
• | Do not damage the screen located on the air inlet
end of the MAF. |
• | Do not touch the sensing elements. |
• | Do not allow solvents and lubricants to come in contact with the
sensing elements. |
• | Use a small amount of a soap based solution in order to aid in
the installation. |
- Install air cleaner
outlet duct to throttle body.
- Install air cleaner outlet duct to MAF sensor.
Tighten
Tighten the hose clamp to 4 N·m (32 lb in).
- Connect the IAT sensor harness connector.
- Install the air cleaner outlet duct retaining
wingnut.
Tighten
Tighten the wingnut to 2 N·m (18 lb in).
- Connect the breather tube to the air cleaner
outlet duct.